The last test I will be taking will be the dec act with writing but im concerned with how long it will take to send the scores to colleges such as UMich or NYU, like will it make it in time. The sept act scores took long enough and now im afraid of delays for the dec 
Since the deadline is Feb 1 for RD, 7 weeks from the test date, I do not think it will be an issue. Just pre-select the schools you want to send to prior to taking the test to minimize delays
You should have your scores in time. September scores were an exception, to an otherwise pretty quick turnaround
I disagree with the poster above, I would wait and see the scores before I send them. Make sure you are sending your best scores.